In Emacs we have a macro that tends to produce the warning comparison is always false due to limited range of data type
when compiling for 64-bit machines. EMACS_INT is 64 bits in that case. Here is the macro: #define FIXNUM_OVERFLOW_P(i) \ ((EMACS_INT)(i) > MOST_POSITIVE_FIXNUM \ || (EMACS_INT) (i) < MOST_NEGATIVE_FIXNUM) When this macro is used on an expression that has type int, it produces those warnings, and there is no way to change the macro to prevent the warnings. We used the workaround of copying the expression into an EMACS_INT in a previous statement, but that is cumbersome and ugly. Is there a way to write the macro so as to suppress this warning? If not, I think one ought to be implemented. I have a suggestion for what it could look like: #define FIXNUM_OVERFLOW_P(i) \ ((EMACS_INT)(int)(i) > MOST_POSITIVE_FIXNUM \ || (EMACS_INT)(int)(i) < MOST_NEGATIVE_FIXNUM) The casts to int could be interpreted as meaning "yes I know this is limited to the range of of ints, so don't warn me about the consequences of that fact." Please respond.
